Vacuum pump



E. RAWSON Feb. 7, 1950 VACUUM PUMP Filed Nov. 12', 1946 Patented Feb. 7,1950 s PATENT oFFlcE VACUUM PUMP Emanuel-Rawson, Chicago, Ill., asslgnorto Rite- Way Products Company, Chicago, Ill., a corporation of DelawareApplication November 12, 1946, Serial No. 709.328 8 Claims. (Cl.230-207) This invention relates to pumps for pumping acter haveheretofore been provided with an external muffler on the discharge sideof the pump which muilier functions also to remove the oil particlesthat are carried by the air stream and permit the separated oil to flowback into the pump casing where it is picked up and recirculated to themoving parts of the pump. Such an external muffler not only increasesthe cost of the pump unit but also is` objectionable in that itconstitutes a projection that extends from ythe ypump caslngand .iseasily damaged. It is one of the objects of the present invention toprovide a pump of the abovev mentioned character wherein the pump casingcontains not only the pumping mechanism but also the muilier and oilseparator and the oil circulating means.

It is a further object of the present invention to provide a pump casingwhich is so constructed Referring specifically to the drawings in'whichi like numerals are used to designate like parts, I indicates a castmetal pump casing with cooling fins 2 on the exterior surface. isopengat opposite sides at one end thereof, the open sides being closedby a pair' of plates bolted thereto, as may be seen from Figures 1, 3and 4. The interior of the casing has a web or partition 3 cast as anintegral part of the casing, which partition divides ythe casing into aninlet compartment 4 in communication with a chamber in which a. rotormember is mounted, as hereinafter described, which rotor chambercommunicates with successive discharge compartments 4a, 4b and 4c, andthence to the pump outlet, as will be more fully described hereinafter.

The compartments 4a, 4b and 4c are in effect one continuous dischargechamber which direct the educated air along a tortuous path. rThe.parti-v tion 3 includes a -horizontarwall portion 3a, an upper wallportionb and a Alower vertical Iwall v portion 3c that has an opening 3dtherethrough.

that it-may be madeas a Vsimple casting the interior of which hasintegrally cast partitions which provide a space for the combinationmuffier and oil separator.

It is a still further object of the present invention to provide adividing partition integrally cast with the rest of a pump casing, whichpartition not only forms the muffler compartment .but also forms a webfor guiding the movable pumping mechanism, which web is so arranged inrelation to the flow of lubricating oil as to facilitate lubrication ofthe movable parts carried by the Web.

The attainment of the above and further objects of the present inventionwill be apparent from the following specification taken in conjunctionwith the accompanying drawing forming a part thereof. I In the drawing:Figure 1 is a plan view of a pump embodying the invention;

Figure 2 is a longitudinal cross sectional view, taken along the line2--2 of Figure 1;

. Figure 3 is a right end view of the pump of Figure l; and

Figure 4 is a fragmentary sectional view taken along the line 4 4 ofFigure 2.y

The inlet compartment 4 has an inletcpening into which is threaded acombination check valve and connecting nipple 5, having external screwthreads 6 on its wall for connection to a system to be evacuated. Thecheck valve includes a ball 1 located within the nipple and normallyrests in open position on a rod 8 away from avalve seat 9. When the pumpis initially stopped air will tend to flow in a reverse directionthrough the pump into the vacuum line connected to the nipple 5. Theball I will then be lifted to its seat 9 to close the valve to preventsuch reverse ow of air through the pump since such reverse flow mighttend to operate the pump in the reverse direction. Under normaloperating on nonoperating conditions the ball is in the ,position shown.

An eccentric or cam I0 is part of a rotatable drive shaft II andactuates a drum-shaped rotor I3. A counterweight I2 is secured to theshaft Il by a nut I4 and a lock nut I4'. A ball bearing is locatedbetween the eccentric and the rotor, this bearing comprisingconventional respective inner and outer raceways I5 and I5 with balls I6interposed therebetween.

' The rotating eccentric Il! moves the drumshaped rotor member I3 in anorbital path with one point of its periphery always in contact with acylindrical wall Il forming the rotoror pumping chamber.

. A blade I8, flanged at one end to provide a foot I9 for attachment tothe rotor member by screws I9a, extends through a slot 20 in the chamberWall l1 and slides in a space 2l between The casing 3 two bearingmembers 22 which are free to oscillate in a socket 23 of the web orpartition 3. Radial ducts 24 may be provided in the bearings 22 tofacilitate lubricating oil flow between the contacting surface of theparts I8, 22 and 23.

The back end of the blade I8 moves in a chamber 26 within the web orpartition 3. An opening 21 for reception of the blade I8 is sufiicientlyoversized to provide clearance for the orbital movement of the blade I8.

A duct 28 in the partition 3 permits the flow of lubricating oil intothe chamber 28.

The discharge compartment lc is provided with a connection 29, such asan elbow, for connection to an exhaust line or for directing the exhaustdirectly into the atmosphere. A muiiier 30, which also acts as an oiltrap or lter, is located in the chamber 4c which is formed by the web orpartition 3 within the casing. The muiller comprises any materialsuitable for separating oil from the ilowing air stream and may comprisea mass of hair, or steel wool, by way of example, which is held in thechamber 4c by a wire screen strainer 32. A top strainer screen 33retains the filter material against being blown out by the moving air.The oil which is separated from the air in the muiiler ows back into thedischarge compartment 4b.

A magnet 34 beneath the lter attracts any` free particles of iron thatmay reach the chamber 4b and thus prevents the circulation of suchparticles with the circulating lubricating oil. The magnet is on the endof a plug which is screw threaded into a threaded opening in the pumpcasing. The opening also acts as a drain opening upon removal of themagnet plug. For convenience in casting the pump casing an opening maybe provided for supporting the core, which opening is then closed by athreaded plug 35 that lls the opening. 1

An oil recirculating tube 31 is mounted on and extends through thepartition 3. The bottom of the tube is near thebottom of the compartmentIb. The opposite end of the tube has a plug 38 which supports the tubeand is in turn thread.

ed into a tapped opening in the partition 3. The

plug 38 has a needle-like bore 33 therein which restricts the rate ofoil tlow therethrough. Oil forced through the tube is ejected as a sprayagainst the underside of a transparent inverted cup 40 the bottom ofwhich ts into a bore 4I in the casing. The cup is detachably held on thecasing inany desired manner, as by a snap spring clip 42. The inspectioncup may be removed to replenish the oil supply. The angle and locationof the bore through which the tube 31 extends is such that it isaccessible for machining operations by insertion of a tool through theopening for the cup I0.

In operation of the pump the shaft Ii rotates counterclockwise as seenin Figure 2, causing the rotor I3 to move in a circular pathconstantlyin contact with the cylinder bore I1. The blade I3 makes a sliding sealat the bearing members 22 and together with the rotor I3 and thepartition 3 separates the inlet compartment 4 from the outletcompartments. 'I'he rotor action draws air from the intake and forces itthrough the discharge compartments 4a, 4b and 4c and out to theatmosphere through the muiller exhaust 23. The air moving through therotor compartment draws with it some of the lubricating oil within thepump. The quantity of lubricating oil initially placed within the casingis sumciently large so that the oil carried by the air moves through thecompartment la as a thick mist. This mist is collected in the mumer anddrains back into the compartment 4b. At the same time the preponderanceo! pressure in the compartment 4b over the pressure in the vacuumcompartment l forces oil to flow up the tube 31 and through the choke 3!where it is emitted as a stream of oil which impinges upon the sightglass or cup 4I and then drops down on the top of the web or partition3. Some of the oil then nows through the duct 23 into the chamber 28 andis effective to lubricate the opposite surfaces o! the blade I3 and alsoto lubricate the contacting surfaces between the bearing 22 and the webor partition 3. The rest oi' the oil drops onto the top of the blade Ilwhere it is picked up by the air stream and serves to lubricate theouter surface of the rotor I3 and the cylindrical wall I1.

As the air which carries with it the oil mist is educted through thepumping chamber it iirst passes through the restricted slot 20 andenters the large discharge compartment la. There its velocity isconsiderably reduced over the velocity of the air initially leaving thepumping chamber, due to the larger cross sectional area oi' thecompartment 4a. The air traveling through the compartment 4a leaves thatcompartment via the small opening 3d in the wall portion 3c. In thecompartment 4b the velocity of the air again changes over what it wasthrough the restricted throat portion or opening 3d. The existence ofthe wall 3c with the opening 3d therein dividing the space intocompartments 4a and lb serves to muiiie the noises of the air eductedthrough the pump. The wall 3c produces changes in the direction o! thenowing air and thus tends to cause some of the oil that is carried bythe moving mass of air to precipitate out. Likewise the air flowing fromthe compartment Ib to the compartment 4c has a substantial change indirection which further tends to separate out oil particles from the airstream. Furthermore, oil that is separated from the air stream as theair stream moves through the munier or iilter material 3l flowsdownwardly through the strainer 32 with the direction of the downwardoil iiow at a substantial angle to the direction of the air ilow intoand below the strainer 32. Therefore air moving upwardly through thestrainer has a smaller tendency to inhibit the downward flow ofseparated oil through the strainer than would be the case if the air andoil were moving in exactly opposite directions.

From the above description it is apparent that 55 by the presentinvention there is provided a vacuum pump having a contained lubricatingsystem and a contained munier and oil trap. By locating the muillerwithin the pump casing the applicant not only eliminates the expense ofan external 30 muffler, but also eliminates the likelihood of damage toan externally extending muiiier. The applicant also eliminates therebythe possibility of air leakage to the atmosphere from the joints betweenthe mufiier and the pump casing. such as e was present in the externalmuillers.

In compliance with the requirements oi the patent statutes I have hereshown and described a preferred embodiment of my invention. It is, 70however, to be understood that the invention is not limited to theprecise construction here shown, the same being merely illustrative ofthe principles of the invention. What I consider new and desire tosecure by Letters Patent is:

p 1. A gas pump comprising a casing having inprior vacuum pumps having iof the casing adjacent to and in line with the end of the tube which isin the inlet compartment.

2. A gas iiow device including a casing having means forming a pumpingchamber at one end thereof, mechanically operable gas flow means in saidchamber, a partition within the casing and constituting an integral partof the casing and together with the gas ow means dividing the casinginto an intake compartment and a discharge compartment bothcommunicating with the pumping chamber, an open ended lubrication tubeextending through the partition to adjacent the bottom of the dischargecompartment and establishing communication between the intake anddischarge compartments for supplying lubricant for said mechanical gasflow means, said partment both communicating with the pumping chamber,the casing having a sight glass opening at the intake compartmentthereof, a sight glass closing said opening, an open ended lubricationcasing having an opening above the top of the tube, a closure for theopening, the tube directing flowing oil against said closure, saidintegral partition further subdividing the discharge compartment toprovide a mufiier chamber at the outlet end of thedischarge'compartment, the discharge compartment havin'gfin addition abaille wall 1 across the same forming va.' 'constriction therein toincrease the'muiiling and oil separating action as an oil and gasmixture moves through the discharge chamber, said baille being anintegral part of the casing.

3. A gas flow device including a casing having means forming a pumpingchamber at one end thereof, mechanically operable gas iiow means in saidchamber, a partition within the casing and constituting an integral partof the casing and together with the gas flow means dividing the casinginto an intake compartment and a discharge compartment bothcommunicating with the pumping chamber, the casing having sight glassopening at the intake compartment thereof, a sight glass closing saidopening, a lubrication tube extending through the partition andestablishing communication between the intake and dischargecompartments, the tube being in line with the sight glass opening sothat it is insertable into and removable from' position by a movementthrough the opening and directs the iiuid flowing therethrough towardsthe sight glass and into the gas stream in the intake compartment forlubricating said mechanical gas flow means, said integral partitionfurther subdividing the discharge compartment to provide a mumer chamberat the outlet end of the discharge compartment, the dischargecompartment having in addition a baffle wall across the same forming econstriction therein to increase the muiliing and oil separating actionas an oil and gas mixture moves through the discharge chamber, saidbaille being an integral part of the casing.-

4. An air pump including a casing having means forming a pumping chamberat one end thereof, rotary air pumping means in said chamber, apartition within the casing and constituting an integral part of thecasing and together with the pumping means dividing the casing into anintake compartment and a discharge comtube extending through thepartition to adjacent the bottom of the discharge compartment andestablishing communication between the intake and dischargecompartments, the tube being in line with the sight glass opening sothat it is insertable into and removable from position by a movementthrough the opening and directs the fluid owing therethrough towards thesight glass and into the gas stream in the yintake compartment forlubricating said pumping means, said integral partition furthersubdividing the discharge compartment to provide a muffler chamber at anend of the discharge compartment, the discharge compartment having inaddition a baille wall across the same forming a constriction therein toincrease the muiiiing and oil separating action as an oil and airmixture moves through the discharge chamber, said b aiiie being anintegral part of the casing. y

5. A gas iiow device including a casing having means forming a pumpingchamber atl one end thereof, mechanically operable gas flow means insaid chamber, a partition within the casing, said partition togetherwith the gas flow means dividing the casing into an intake compartmentand a discharge compartment both communicating with the pumping chamber,the casing having a sightgglass opening at the intake compartmentthereof, a sight glass closing said opening, and a lubrication tubeextending through the partition and establishing communication betweenthe intake and discharge compartments, the tube discharging into theregion of the sight glass opening.

6. A gas flow device including a casing having means forming a pumpingchamber at one end thereof, mechanically operated gas flow means in saidchamberfa partition within the casing, said partition together with thegas ow means dividing the casing into an intake compartment and adischarge compartment both communicating with the pumping chamber, thecasing having a sight glass opening at the intake compartment thereof,`a sight glass closing said opening, a 1ubricating tube extending throughthe partition and establishing communication between the intake and thedischarge compartments, the end of the tube being in the region of thesight glass opening andthe tube being insertable into and removable fromposition by a movement through the opening, said tube directing thelubricant flowing therethrough towards the sight glass opening, saidlubricant then moving into the gas stream in the intake compartment forlubricating said mechanical gas now means.

EMANUEL RAWBON.

REFERENCES CITED The following references are of record in the ille ofthis patent:

